bug#60953: The :match predicate with large regexp in tree-sitter font-lock seems inefficient

[Dmitry Gutov]

On 26/01/2023 20:07, Dmitry Gutov wrote:
> One could hope to avoid recreating the list of predicates on every 
> match, but that seems to be a limitation of the TS API: 
> ts_query_predicates_for_pattern requires a second argument, 
> match.pattern_index. Maybe we could memoize that, though?

Speaking of memoization, here is a POC patch.

It's a definite improvement: with the attached :match almost reaches the 
performance of :pred. Not sure why it's still not faster, though.

(I also tried a more comprehensive memoization using a hash table, the 
resulting performance was slightly worse.)

memoize_simple.diff
Description: Text Data